The present invention relates to a novel molded air freshener.
Various proposals have heretofore been offered about air fresheners using various kinds of thermoplastic resins and perfumes supported thereon.
Ethylene-vinyl acetate copolymer resin (hereinafter referred to simply as "EVA") absorbs perfumes most easily among all thermoplastic resins and it permits the absorbed perfumed to exhibit volatilizing properties which are extremely superior. And air fresheners using EVA of such superior characteristics as perfume carriers halve come to appear in this industry as "plastic-based" air fresheners. They are morphologically classified broadly into two types --(a) a pellet type in which perfumes are absorbed in molding pellets of EVA resin and (b) a molded product type in which perfume-absorbed EVA pellets, as molding material, are melt-molded directly according to a known molding method such as, for example, injection molding or extrusion.
The pellet type (a) is advantageous in that there is no fear of degradation of perfume because a pellet type air freshener is prepared by contacting a perfume with EVA pellets for several hours at a room temperature or thereabouts. However, since the pellets are apt to fall from their container, it is inevitably necessary for the container to be a closed type having vent slits smaller in diameter than the pellets. For this reason and because of pellets, the decrease of volume caused by volatilization of the perfume is small and so it is difficult to visually perceive an end point indicating the end of the volatilization.
The molded product type (b) is advantageous in that because of a melt-molded product of a perfume-containing EVA, the decrease of volume caused by volatilization of the perfume is larger than that in pellets and so it is easy to perceive the aforesaid end point easily. But it is disadvantageous in that the heat deterioration of perfume is unavoidable because the molding temperature reaches 100.degree. C. or so even at the lowest.
To make up for such drawback, first EVA alone may be subjected to molding and then the resultant molded product immersed in a perfume at room temperature, allowing the perfume to be adsorbed in the molded product. In this method, however, an extremely long time is required for the absorption, and due to the absorption after molding, there occur distortional deformations and roughening of the surface, often resulting in marked impairment of the external appearance. Therefore, the products obtained by such method are difficult to use practically and in fact no products that are presumably obtained by such method are on the market.